Fei Wei was a legendary archer in ancient China, renowned for his extraordinary skill
A young man named Ji Chang, having heard of the legendary archer Fei Wei's reputation, came to apprentice under him, eager to master the art of archery. Fei Wei instructed him, "First, learn to blink without moving your eyes, then we can discuss archery." Ji Chang returned home and lay beneath his wife's loom, staring at the moving shuttle without blinking for two years. When he could poke a needle tip near his eye without flinching, he reported back. Fei Wei said, "Not enough. Now learn to see clearly. When you can magnify a small object as large as a cartwheel, come back." Ji Chang hung a louse on a window with a horsehair and stared at it for three years, until the louse appeared as big as a carriage wheel. He then shot it, piercing its heart without breaking the hair. Fei Wei declared, "You have mastered it." Source: *Liezi*, "Tang Wen"
Fei Wei told him, "You must first learn not to blink before you can talk about learning archery."
Ji Chang returned home and lay on his back under his wife's loom, staring unblinking at the shuttle as it flew back and forth. After two years of this practice, even when a needle point was jabbed toward the corner of his eye, he wouldn't flinch.
So, he went back to Fei Wei. Fei Wei said, "This is still not enough. You must further train your eyesight until the smallest things appear large to you and the finest details appear coarse."
Ji Chang returned home, tied a louse to a fine horsehair and hung it by the window, staring at it day after day. Over time, the louse grew in his sight to the size of a grasshopper, then a bird, and after three years, it appeared as large as a cartwheel. When he looked at other objects, they seemed magnified beyond measure.
Ji Chang drew his bow, and with a single arrow, struck the louse dead center, yet the hair from which it hung remained unbroken.
Ji Chang went to find Fei Wei again. Fei Wei said happily, "You have mastered it!"
Thus, Ji Chang, like his master Fei Wei before him, became a legendary archer renowned throughout the land.
Later, someone combined it with the story of "Hitting a Willow Leaf from a Hundred Paces" to form the phrase "Piercing a Louse and a Willow Leaf," used to describe superb archery.
Source: *Liezi*, Chapter "Tang Wen"
Meaning of the Idiom: Later, the Chinese idiom "贯虱穿杨" came to describe superb archery.